The invention relates to a device for the flame treatment of a work-piece, including upper and lower preheating blocks which are both arranged on a holding means including a gas distribution system with the preheating blocks being arranged at a distance from one another for the purpose of forming a flame-oxygen-duct.
In the case of the conventional flaming process, the flame-burner is first of all directed toward the work-piece to be subjected to the flame treatment. After turning on the combustible gas and lighting the same, the work-piece is heated by means of the preheating flames directed toward the surface of the work-piece and this procedure is carried out up to the time the ignition temperature of the metal is attained.
The preheating process takes a considerable time, but an ignition wire or iron powder can be inserted into the heating flame to accelerate the preheating process. This is particularly expedient in cases of cold blocks or slabs, in order to eliminate an otherwise undesirably long preheating time.
The zone to be swept over by the heating flames usually extends over the entire width of the flame burner or when several flame burners are joined together to one aggregate, over the width of the latter and such a zone is disadvantageous. When using an ignition-aid, such as, for example, iron powder, it is therefore necessary to apply the powder likewise over the entire width of the zone to be treated with the flame. This, however, requires a considerable quantity of iron powder, and a correspondingly wide powder-nozzle. The flaming costs increase because of such complex powder-nozzle.
It had already been suggested to restrict locally the ignition place on the work-piece to be subjected to the action of the flame. That is, under those conditions the ignition place no longer is of an order of magnitude which corresponds to the width of the flame burner, but is of a considerably smaller order of magnitude. For this purpose, an electrode is installed in front of the flameburner. This electrode is electrically ignited and, in this manner, a locally restricted ignition place is created ahead of the flame-burner in the flaming-zone, from which ignition place the molten metal is spread over the entire flame-path-width by means of the flame-oxygen jet lead in after the ignition. This is described in U.S. Pat. No. 2,513,425.
It is disadvantageous here that an electrical ignition device of its own has to be assigned to the flame-burner in addition to an elaborate control system and that beyond this, the electrical ignition device, after ignition had taken place, has to be removed from the flaming-zone by means of an additional pivoting device.
It is the task of the present invention to create a flame-burner by means of which a locally restricted ignition can be carried out without elaborate auxiliary means, such as e.g. an ignition electrode.